OpenVPN: T3350: Changed custom options for OpenVPN processing

Custom OpenVPN options moved back to the command line from a
configuration file. This should keep full compatibility with the
`crux` branch, and allows to avoid mistakes with parsing options
that contain `--` in the middle.
The only smart part of this - handling a `push` option. Because
of internal changes in OpenVPN, previously it did not require an
argument in the double-quotes, but after version update in
`equuleus` and `sagitta` old syntax became invalid. So, all the
`push` options are processed to add quotes. The solution is still
not complete, because if a single config line contains `push` with
other options, it will not work, but it is better than nothing.

(cherry picked from commit 3fd2ff423b6c6e992b2ed531c7ba99fb9e1a2123)

4 files changed, 32 insertions, 13 deletions

diff --git a/data/templates/openvpn/server.conf.tmpl b/data/templates/openvpn/server.conf.tmpl
index c96b57fb8..c2b0c2ef9 100644
--- a/data/templates/openvpn/server.conf.tmpl
+++ b/data/templates/openvpn/server.conf.tmpl
@@ -257,16 +257,3 @@ auth {{ hash }}
 auth-user-pass {{ auth_user_pass_file }}
 auth-retry nointeract
 {% endif %}
-
-{% if openvpn_option is defined and openvpn_option is not none %}
-#
-# Custom options added by user (not validated)
-#
-{%   for option in openvpn_option %}
-{%     for argument in option.split('--') %}
-{%       if argument is defined and argument != '' %}
---{{ argument }}
-{%       endif %}
-{%     endfor %}
-{%   endfor %}
-{% endif %}
diff --git a/data/templates/openvpn/service-override.conf.tmpl b/data/templates/openvpn/service-override.conf.tmpl
new file mode 100644
index 000000000..069bdbd08
--- /dev/null
+++ b/data/templates/openvpn/service-override.conf.tmpl
@@ -0,0 +1,20 @@
+[Service]
+ExecStart=
+ExecStart=/usr/sbin/openvpn --daemon openvpn-%i --config %i.conf --status %i.status 30 --writepid %i.pid
+{%- if openvpn_option is defined and openvpn_option is not none %}
+{%   for option in openvpn_option %}
+{#     Remove the '--' prefix from variable if it is presented #}
+{%     if option.startswith('--') %}
+{%       set option = option.split('--', maxsplit=1)[1] %}
+{%     endif %}
+{#     Workaround to pass '--push' options properly. Previously openvpn accepted this option without values in double-quotes #}
+{#     But now it stopped doing this, so we need to add them for compatibility #}
+{#     HOWEVER! This is a raw option and we do not promise that this or any other trick will work for all the cases. #}
+{#     Using 'openvpn-option' you take all responsibility for compatibility for yourself. #}
+{%     if option.startswith('push') and not (option.startswith('push "') and option.endswith('"')) %}
+{%       set option = 'push \"%s\"'|format(option.split('push ', maxsplit=1)[1]) %}
+{%     endif %}
+ --{{ option }}
+{%-   endfor %}
+{% endif %}
+
diff --git a/src/conf_mode/interfaces-openvpn.py b/src/conf_mode/interfaces-openvpn.py
index 5d537dadf..4e3c19be2 100755
--- a/src/conf_mode/interfaces-openvpn.py
+++ b/src/conf_mode/interfaces-openvpn.py
@@ -51,6 +51,7 @@ user = 'openvpn'
 group = 'openvpn'
 
 cfg_file = '/run/openvpn/{ifname}.conf'
+service_file = '/run/systemd/system/openvpn@{ifname}.service.d/20-override.conf'
 
 def checkCertHeader(header, filename):
     """
@@ -434,6 +435,11 @@ def generate(openvpn):
     if os.path.isdir(ccd_dir):
         rmtree(ccd_dir, ignore_errors=True)
 
+    # Remove systemd directories with overrides
+    service_dir = os.path.dirname(service_file.format(**openvpn))
+    if os.path.isdir(service_dir):
+        rmtree(service_dir, ignore_errors=True)
+
     if 'deleted' in openvpn or 'disable' in openvpn:
         return None
 
@@ -477,6 +483,12 @@ def generate(openvpn):
     render(cfg_file.format(**openvpn), 'openvpn/server.conf.tmpl', openvpn,
            formater=lambda _: _.replace(""", '"'), user=user, group=group)
 
+    # Render 20-override.conf for OpenVPN service
+    render(service_file.format(**openvpn), 'openvpn/service-override.conf.tmpl', openvpn,
+           formater=lambda _: _.replace(""", '"'), user=user, group=group)
+    # Reload systemd services config to apply an override
+    call(f'systemctl daemon-reload')
+
     return None
 
 def apply(openvpn):
diff --git a/src/etc/systemd/system/openvpn@.service.d/override.conf b/src/etc/systemd/system/openvpn@.service.d/10-override.conf
index 03fe6b587..03fe6b587 100644
--- a/src/etc/systemd/system/openvpn@.service.d/override.conf
+++ b/src/etc/systemd/system/openvpn@.service.d/10-override.conf